Israeli sources confirmed late tonight that Soviet SAM-2 and SAM-3 rockets have been moved toward the bank of the Suez Canal on the Egyptian side. The activity took place in the central sector of the canal, between the Cairo-Ismailia and Cairo-Suez roads. An Israeli radio commentator said today that the deployment had taken place a few hours after the cease-fire took effect at 1 a.m. Saturday, Cairo time. There had been speculation that the missiles might have been deployed just prior to the cease-fire but not noticed until afterwards. (See story page 1.)